A method for efficiently synthesizing dodecyl alcohol ester

Abstract

The present invention discloses a method for efficiently synthesizing dodecyl alcohol ester. Under the catalysis of a novel composite base catalyst, dodecyl alcohol ester is synthesized in one step. Compared with the traditional process, it not only shortens the reaction process flow, but also reduces the post-treatment process of the product, and improves the purity and recovery rate of the product.

Description

Technical Field

[0001] The present invention relates to the field of chemical product production, and particularly to a method for efficiently synthesizing dodecyl alcohol ester. Background Art

[0002] Dodecyl alcohol ester (CS-12) is a non-water-soluble diol ester with a high boiling point and a low freezing point. It is non-toxic itself and has very good compatibility with a variety of solvents. It is a generally recognized green solvent and is widely used in various aspects.

[0003] CS-12 is also an excellent film-forming aid for coatings. Compared with other film-forming aids, due to its low freezing point, it can effectively reduce the minimum film-forming temperature of latex paint, promote the film formation of latex paint, has excellent wet film properties, can improve the film properties of latex paint, and has good paint-making stability, thereby improving the adhesion rate, flatness, brightness, washability, anti-sagging characteristics and leveling property of the paint.

[0004] The lubricant synthesized with the nonanoate of CS-12 as the base material has particularly excellent stability, good performance index at low temperature and low elastic expansion index. Compared with other esters, the double-ester lubrication performance of CS-12 is excellent.

[0005] Due to the increasing attention of researchers to the application value of dodecyl alcohol ester, more and more scientific research personnel have studied its synthesis method.

[0006] The synthesis methods of dodecyl alcohol ester are divided into indirect synthesis method and direct synthesis method. The indirect synthesis method is carried out under weakly acidic conditions. First, isobutyraldehyde undergoes three-molecule self-polymerization to form triisobutylaldehyde, and then triisobutylaldehyde is catalytically hydrogenated to produce 2,2,4-trimethyl-1,3-pentanediol (TMPD) and isobutanol. TMPD is then esterified with isobutyric acid to obtain the crude product of dodecyl alcohol ester, and finally the product is obtained through separation and purification. The advantages of this process are fewer by-products, and the disadvantages are that the process is relatively complex, the utilization rate of isobutyraldehyde is low, and isobutyric acid needs to be added additionally, increasing the raw material consumption; the direct synthesis method is carried out under weakly alkaline conditions. First, isobutyraldehyde undergoes aldol condensation reaction by itself to form 2,2,4-trimethyl-3-hydroxypentanal, and the obtained product further reacts with isobutyraldehyde under alkaline conditions to obtain the crude product, and the crude product is then separated and purified to obtain a high-purity product meeting the standard. The direct synthesis method has a relatively simple process, small equipment investment, and easily available raw materials, but there are many side reactions during the reaction process. Summary of the Invention

[0007] The purpose of the present invention is to provide a method for efficiently synthesizing dodecyl alcohol ester. Under the catalytic action of a novel composite base catalyst, dodecyl alcohol ester is synthesized in one step. Compared with the traditional process, not only the reaction process flow is shortened, but also the post-treatment process of the product is reduced, and the purity and recovery rate of the product are improved.

[0008] To achieve the above object, the solution of the present invention includes the following:

[0009] In the first aspect of the present invention, a method for preparing a novel composite catalyst is provided, including the following steps:

[0010] (a) Using calcium nitrate, zinc nitrate, and aluminum nitrate as raw materials and urea as a precipitating agent, a catalyst precursor Ca-Zn-Al hydrotalcite is prepared by the homogeneous precipitation method, and then a Ca-Zn-Al-O solid base is obtained by high-temperature calcination;

[0011] (b) Dissolve choline bicarbonate and 1-butyl-3-methylimidazolium bromide in a mixed solution of ultrapure water and diethylamine, and inject it into the system containing Ca-Zn-Al-O solid base at a certain flow rate for infiltration; after completion, wash with water until the pH of the effluent is 7, add a certain amount of phenol to the Ca-Zn-Al-O solid base, mix well at room temperature, after the reaction is completed, evaporate to remove the water, and then dry in vacuum to obtain a high-purity novel composite catalyst.

[0012] Among them, in step (a), the molar ratio of calcium nitrate, zinc nitrate, and aluminum nitrate is 1:1-2:1-3;

[0013] The molar ratio of urea to nitrate in the raw materials is n(urea):n(NO3 - ) = 2:1 to 1:2, preferably 1.5:1 to 1:1.5, more preferably 1.2:1 to 1:1.2;

[0014] The mass ratio of deionized water to (raw materials + precipitating agent) is 2:1 to 1:3; preferably 1.5:1 to 1:1.5, more preferably 1.2:1 to 1:1.2;

[0015] The precipitation reaction temperature is 50-70°C; the calcination temperature is 200-240°C.

[0016] In a specific embodiment, the operation of step a includes:

[0017] Weigh a certain amount of Ca(NO3)2, Zn(NO3)2·6H2O, Al(NO3)3·9H2O, urea, and deionized water, stir and dissolve them in a beaker to obtain a homogeneous mixed solution, pour it into a hydrothermal synthesis reactor, put it into a vacuum drying oven, react at 50-70°C for 2-5 h, take it out and cool to room temperature. Pour the cooled solution into a beaker, filter it with a Buchner funnel, and wash with water until the pH of the washing liquid is 7. Place the filtered cake obtained by suction filtration in a vacuum drying oven and dry it at 50-80°C for 5-10 h. Put the dried solid into a crucible, place it in a muffle furnace, and calcine it at 200-240°C for a certain time to obtain a Ca-Zn-Al-O solid base.

[0018] In the present invention, in step (b), the molar ratio of choline hydrogencarbonate to 1-butyl-3-methylimidazolium bromide is 1:1 to 1:4, and the mass ratio of ultrapure water to diethylamine is 1:1 to 1:3;

[0019] The total addition amount of choline hydrogencarbonate and 1-butyl-3-methylimidazolium bromide and the mass ratio of the Ca-Zn-Al-O solid base is 2:1 to 4:1;

[0020] The infiltration time is 2 to 5 h;

[0021] The mass ratio of phenol to the Ca-Zn-Al-O solid base is 1:1 to 1:2.5.

[0022] The second aspect of the present invention relates to the application of the composite catalyst prepared according to the above method in the synthesis of dodecyl alcohol ester. It includes:

[0023] (1) A certain amount of isobutyraldehyde enters a fixed-bed reactor filled with the above composite catalyst for one-step synthesis, wherein the treatment amount of the composite catalyst is 50 - 150 g of isobutyraldehyde / g of catalyst; the reactor uses an external circulation heat exchanger to remove a large amount of reaction heat to ensure that the reaction proceeds at a constant temperature;

[0024] (2) The reaction solution is adsorbed by an acidic resin to obtain a liquid with a pH of 7, and the light component by-products are removed by vacuum distillation to finally obtain a high-purity dodecyl alcohol ester product.

[0025] In the present invention, in step (1), the prepared composite catalyst is filled with catalysts having different particle sizes from bottom to top in ascending order of particle size, and Al2O3 balls are installed at the top of the catalyst bed to prevent the catalyst bed from scattering;

[0026] The reaction temperature is 60 - 74 °C, and the reaction time is 1.5 - 2 h.

[0027] In the present invention, in step (2), the acidic resin can be a strongly acidic cation exchange resin or a weakly acidic cation exchange resin, such as the strongly acidic cation exchange resin 001*7Na (732) and the macroporous weakly acidic acrylic cation exchange resin D113. Preferably, the resin is a mixture of 732 and D113 in a mass ratio of 1:1 to 1:2;

[0028] The operating conditions of vacuum distillation are: the tower operating pressure is 0.1 - 0.3 bar, the number of tower plates is 30 - 35, the feed is in the middle of the tower, the top temperature of the tower is 60 - 65 °C, the bottom temperature of the tower is 125 - 150 °C, and the reflux ratio is 2:1 to obtain a dodecyl alcohol ester with high purity and high yield.

[0029] The positive effects of the present invention are as follows:

[0030] (1) Under the action of the composite catalyst synthesized in the present invention, dodecyl alcohol ester can be synthesized in one step through mild reaction conditions.

[0031] (2) The post-treatment process of the reaction solution is simple. Only through resin adsorption and vacuum distillation operations, a high-purity product is obtained, and the yield of the product is relatively high, reaching more than 93%.

[0032] (3) The degree of automation of the entire process is high, which is conducive to realizing industrial continuous production. Specific Embodiments

[0033] The following examples are not used to limit the scope of implementation of the present invention. If the present invention is modified or equivalently replaced without departing from the spirit and scope of the present invention, it shall be covered by the protection scope of the claims of the present invention.

[0034] The 80 wt% choline bicarbonate aqueous solution is from Sigma-Aldrich;

[0035] The 98 wt% 1-butyl-3-methylimidazolium bromide is from Jinan Xinda Chemical Co., Ltd.;

[0036] The strong acidic cation exchange resin 001*7Na (732) and the macroporous weak acidic acrylic cation exchange resin D113 are both from Bengbu Dongli Chemical Co., Ltd.

[0037] The recovery rate of dodecyl alcohol ester is analyzed and calculated by liquid chromatography equipped with an ultraviolet detector. The liquid chromatography is the Agilent 1200 series, equipped with a C18 liquid chromatography column. The column temperature is set at 40 °C. Acetonitrile and 0.05 mol / L NaH2PO4 solution are used as the mobile phase, and the flow rate is 1.0 mL / min. Detection is carried out at a wavelength of 360 nm by the ultraviolet detector, and quantitative analysis is carried out by the external standard method. Before injection, the sample is appropriately diluted with ultrapure water, and after sufficient derivatization with an excessive amount of dinitrofluorobenzene solution, it is then injected for analysis.

[0038] Example 1

[0039] Catalyst Preparation:

[0040] Take Ca(NO3)2, Zn(NO3)2·6H2O, Al(NO3)3·9H2O, urea and deionized water. Among them, n[Ca(NO3)2]:n[Zn(NO3)2·6H2O]:n[Al(NO3)3·9H2O] = 1:1.5:1.5, the molar ratio of urea to nitrate in the raw materials is 1:1.2, and the mass ratio of deionized water to (raw materials + urea) is 1.2:1. Stir and dissolve in a beaker to obtain a homogeneous mixed solution, pour it into a hydrothermal synthesis reactor, place it in a vacuum drying oven, react at 50 °C for 3.5 h, take it out and cool to room temperature. Pour the cooled solution into a beaker, perform suction filtration with a Buchner funnel, and wash with water until the pH of the washing liquid is 7. Place the filter cake obtained by suction filtration in a vacuum drying oven and dry at 70 °C for 10 h. Put the dried solid into a crucible, place it in a muffle furnace, and calcine at 240 °C for 2 h to obtain a Ca-Zn-Al-O solid base;

[0041] Take choline bicarbonate and 1-butyl-3-methylimidazolium bromide with a molar ratio of 1:2.5, dissolve them in a mixed solution of ultrapure water and diethylamine with a mass ratio of 1:1.8. The total addition amount of choline bicarbonate and 1-butyl-3-methylimidazolium bromide and the mass ratio of the Ca-Zn-Al-O solid base is 3:1. Infuse it into the system containing Ca-Zn-Al-O at 0.5 m / s for infiltration. After infiltration for 3 h, wash with water until the pH of the effluent is 7. Add a certain amount of phenol to the Ca-Zn-Al-O solid base, and the mass ratio of phenol to the Ca-Zn-Al-O solid base is 1:2.5. After fully mixing and reacting at room temperature, evaporate to remove the water, and then vacuum dry to obtain a high-purity novel composite catalyst.

[0042] Synthesize dodecyl alcohol ester:

[0043] Load the prepared novel composite base catalyst into a fixed-bed reactor according to different particle sizes of the catalyst. Load the catalysts with gradually increasing particle sizes from bottom to top. There are Al2O3 balls at the top of the catalyst bed to prevent the catalyst bed from scattering. Add isobutyraldehyde to the reactor (the catalyst treatment amount is 100 g of isobutyraldehyde / g of catalyst), the reaction temperature is 64 °C, and the reaction time is 2 h. The reaction completion liquid is adsorbed by a resin adsorption column mixed with 732 and D113 in a mass ratio of 1:2 to obtain a liquid with a pH of 7. Then, it is rectified by a vacuum rectification column. The operating pressure of the column is 0.2 bar, the number of trays is 32, the feed is in the middle of the column, the top temperature of the column is 61 °C, the bottom temperature of the column is 125 °C, and the reflux ratio is 2:1 to obtain a high-purity dodecyl alcohol ester with a purity of 99.5 wt%, and the product yield is 96%.

[0044] Example 2

[0045] Catalyst preparation:

[0046] Take Ca(NO3)2, Zn(NO3)2.6H2O, Al(NO3)3.9H2O, urea and deionized water, where n[Ca(NO3)2]:n[Zn(NO3)2.6H2O]:n[Al(NO3)3.9H2O]=1:1.4:1.8, the molar ratio of urea to nitrate in the raw material is 1:1.35, and the mass ratio of deionized water to (raw material + urea) is 1.5:1. Stir and dissolve in a beaker to obtain a uniform mixed solution, pour it into a hydrothermal synthesis reactor, put it into a vacuum drying oven, react at 55°C for 4h, take it out and cool it to room temperature. Pour the cooled solution into a beaker, filter it with a Buchner funnel, and wash it with water until the pH of the washing liquid is 7. Place the filter cake obtained by filtration in a vacuum drying oven and dry it at 70°C for 10h. The dried solid was placed in a crucible, put into a muffle furnace, and calcined at 230°C for 4 hours to obtain a Ca-Zn-Al-O solid base.

[0047] Choline bicarbonate and 1-butyl-3-methylimidazolium bromide in a molar ratio of 1:2 are dissolved in a mixed solution of ultrapure water and diethylamine in a mass ratio of 1:1.5, wherein the mass ratio of the total amount of choline bicarbonate and 1-butyl-3-methylimidazolium bromide added to the Ca-Zn-Al-O solid base is 2:1, and are injected into a system containing the Ca-Zn-Al-O solid base at a flow rate of 0.8 m / s for infiltration. After infiltration for 3 hours, the system is washed with water until the pH value of the effluent is 7. A certain amount of phenol is added to the Ca-Zn-Al-O solid base, and the mass ratio of phenol to the Ca-Zn-Al-O solid base is 1:2.1. After the reaction is fully mixed at room temperature, the water is evaporated to remove the water, and then the system is dried in vacuum to obtain a high-purity novel composite catalyst.

[0048] Synthetic dodecyl alcohol ester:

[0049] The prepared new composite alkali catalyst is loaded into a fixed bed reactor according to the different particle sizes of the catalyst, and the catalysts with small to large particle sizes are loaded from bottom to top. Al2O3 balls are installed on the top of the catalyst bed to prevent the catalyst bed from scattering. Isobutyraldehyde is added to the reactor (the catalyst treatment amount is 100g isobutyraldehyde / g catalyst) with a reaction temperature of 67℃ and a reaction time of 1.5h. The reaction liquid is adsorbed by a resin adsorption column mixed with a strong acid cation exchange resin 001*7Na (732) and a macroporous weak acid acrylic acid cation exchange resin D113 in a mass ratio of 1:1.75 to obtain a liquid with a pH of 7. It is then distilled in a vacuum distillation tower with an operating pressure of 0.25 bar, 35 plates, feeding in the middle of the tower, a top temperature of 63℃, a bottom temperature of 135℃, a reflux ratio of 2:1, and a high-purity dodecanol ester with a purity of 98.5wt% is obtained, and the product yield is 94%.

[0050] Example 3

[0051] Catalyst preparation:

[0052] Take Ca(NO3)2, Zn(NO3)2.6H2O, Al(NO3)3.9H2O, urea and deionized water, where n[Ca(NO3)2]:n[Zn(NO3)2.6H2O]:n[Al(NO3)3.9H2O]=1:2:3, the molar ratio of urea to nitrate in the raw material is 1:2, and the mass ratio of deionized water to (raw material + urea) is 2:1. Stir and dissolve in a beaker to obtain a uniform mixed solution, pour it into a hydrothermal synthesis reactor, put it into a vacuum drying oven, react at 65°C for 4.5h, take it out and cool it to room temperature. Pour the cooled solution into a beaker, filter it with a Buchner funnel, and wash it with water until the pH of the washing liquid is 7. Place the filter cake obtained by filtration in a vacuum drying oven and dry it at 65°C for 10h. The dried solid was placed in a crucible, put into a muffle furnace, and calcined at 200° C. for 5 h to obtain a Ca-Zn-Al-O solid base.

[0053] Choline bicarbonate and 1-butyl-3-methylimidazolium bromide in a molar ratio of 1:4 are dissolved in a mixed solution of ultrapure water and diethylamine in a mass ratio of 1:3, wherein the mass ratio of the total amount of choline bicarbonate and 1-butyl-3-methylimidazolium bromide added to the Ca-Zn-Al-O solid base is 4:1, and are injected into a system containing the Ca-Zn-Al-O solid base at a flow rate of 1 m / s for infiltration. After infiltration for 5 hours, the system is washed with water until the pH value of the effluent is 7. A certain amount of phenol is added to the Ca-Zn-Al-O solid base, and the mass ratio of phenol to the Ca-Zn-Al-O solid base is 1:2.5. After the reaction is fully mixed at room temperature, the water is evaporated to remove the water, and then the system is vacuum dried to obtain a high-purity novel composite catalyst.

[0054] Synthetic dodecyl alcohol ester:

[0055] The prepared new composite alkali catalyst is loaded into a fixed bed reactor according to the different particle sizes of the catalyst, and the catalysts with small to large particle sizes are loaded from bottom to top. Al2O3 balls are installed on the top of the catalyst bed to prevent the catalyst bed from scattering. Isobutyraldehyde is added to the reactor (the catalyst treatment amount is 100g isobutyraldehyde / g catalyst), the reaction temperature is 74℃, and the reaction time is 1.5h. The reaction completed liquid is adsorbed by a resin adsorption column mixed with a strong acid cation exchange resin 001*7Na(732) and a macroporous weak acid acrylic acid cation exchange resin D113 in a mass ratio of 1:1.25 to obtain a liquid with a pH of 7. Then it is distilled in a vacuum distillation tower with an operating pressure of 0.1bar, 35 plates, feeding in the middle of the tower, a top temperature of 60℃, a bottom temperature of 125℃, a reflux ratio of 2:1, and a high-purity dodecanol ester with a purity of 94wt% is obtained, and the product yield is 93%.

Claims

1. A preparation method of a composite catalyst, comprising the following steps: (a) Using calcium nitrate, zinc nitrate, and aluminum nitrate as raw materials and urea as a precipitating agent, a catalyst precursor Ca-Zn-Al hydrotalcite-like compound is prepared by the homogeneous precipitation method, and then a Ca-Zn-Al-O solid base is obtained by high-temperature calcination; wherein: the molar ratio of calcium nitrate, zinc nitrate, and aluminum nitrate is 1:1-2:1-3; the molar ratio of urea to nitrate in the raw materials is nurea:nNO3 - = 2:1 to 1:2; (b) Take choline bicarbonate and 1-butyl-3-methylimidazolium bromide and dissolve them in a mixed solution of ultrapure water and diethylamine, inject them into a system containing Ca-Zn-Al-O solid base for infiltration; after completion, wash with water until the pH of the effluent is 7, add a certain amount of phenol to the Ca-Zn-Al-O solid base, mix well at room temperature, after the reaction is completed, evaporate to remove water, and then dry under vacuum to obtain the composite catalyst; wherein: the molar ratio of choline bicarbonate to 1-butyl-3-methylimidazolium bromide is 1:1 to 1:4; the mass ratio of the total addition amount of choline bicarbonate and 1-butyl-3-methylimidazolium bromide to the mass of the Ca-Zn-Al-O solid base is 2:1 to 4:1; the mass ratio of phenol to the Ca-Zn-Al-O solid base is 1:1 to 1:2.

5.

2. The method according to claim 1, wherein In step (a), the precipitation reaction temperature is 50-70°C; the calcination temperature is 200-240°C.

3. Use of the composite catalyst prepared by the method according to any one of claims 1-2 in the synthesis of dodecyl alcohol ester from isobutyraldehyde.

4. A method for synthesizing dodecyl alcohol ester, comprising: (1) Isobutyraldehyde enters a fixed-bed reactor filled with the composite catalyst prepared by the method according to any one of claims 1-2 for one-step synthesis; (2) The reaction solution is adsorbed by an acidic resin to obtain a liquid with a pH of 7, and the light-component by-products are removed by vacuum distillation to obtain a dodecyl alcohol ester product.

5. The method according to claim 4, wherein The reaction temperature is 60-74°C, and the reaction time is 1.5-2 h.

6. The method according to claim 4 or 5, wherein The acidic resin is selected from strongly acidic cation exchange resins and weakly acidic cation exchange resins.

7. The method according to claim 6, wherein The acidic resin is selected from strongly acidic cation exchange resin 001*7Na and macroporous weakly acidic acrylic cation exchange resin D113.

8. The method according to claim 7, wherein The acidic resin is a resin obtained by mixing strongly acidic cation exchange resin 001*7Na and macroporous weakly acidic acrylic cation exchange resin D113 in a mass ratio of 1:1 to 1:2.